This application claims priority upon German application 198 39 469.1 filed Aug. 29, 1998, which is incorporated herein by reference.
The invention relates to a bearing ring for supporting a protective device at a rotating driveshaft. The driveshaft drives, or is in a driveline for, agricultural implements. The bearing ring engages an annular groove of a component of the driveshaft.
Bearing rings are described in U.S. Pat. No. 4,435,166. The bearing ring is divided in one place so that it can be slid over the compartment or the joint yoke. The bearing ring can be made to engage the annular groove of the joint yoke. The bearing ring is provided with means to attach itself to a protective cone and protective tubes surrounding the profiled tubes of the driveshaft. The bearing ring includes the integrally formed-on portions which engage the annular groove.
It is an object of the present invention to provide a bearing ring which has a long service life even in the case of high sliding speeds and loads acting from the outside.
In accordance with the invention, a bearing ring includes a basic ring portion and a bearing portion. The basic ring portion connects to a component of the protective device. The basic ring portion and the bearing ring portion are of different types of plastics. The bearing ring portion is a plastic material which belongs to the material group of polyetheretherketon (PEEK).
Such a composite structure is advantageous because it is possible to choose a relatively cost-effective flexible material for the basic ring portion, for example polyamide, and a different material for the bearing portion. The bearing portion material, even at high relative sliding speeds and in the case of external loads, has a high temperature resistance which is clearly higher than that of the material of the basic ring portion. Overall, such a composite design also achieves an acceptable cost-effective solution. The permanent service temperatures of such PEEK materials are in excess of the temperature range of 200 to 250 degrees centigrade. Even at high temperature, the thermal expansion coefficient is low relative to that of the usually used materials. Thus, even at such high temperatures, there is no need to provide large tolerances which adversely affect the running characteristics in order to ensure accurate rotation of the driveshaft in the protective device. In addition, the invention enables a lubrication-free bearing operation.
According to a first embodiment, the bearing portion is connected to the basic ring portion in a material-locking way. In a second embodiment, the bearing portion is provided as a separate component. The bearing portion is connected to the basic ring portion in a form-fitting way. In such a case, it is advantageous for the bearing ring portion to include a plurality of bearing segments. To be able to receive the bearing segments, the basic ring portion has recesses which start from its bore and extend over part of the circumference of the ring portion. The bearing segments are arranged in the recesses. The bearing segments additionally partially embrace the side faces of the basic ring portion.
In order to fix the bearing segments, the basic ring portion includes recesses which are resiliently engaged by projections on bearing segments. Good running characteristics are achieved if the inwardly pointed faces of the bearing segments include chamfers at their ends. Particularly advantageous service life characteristics are achieved if a PEEK material with a fiber content is selected, with the fibers being carbon fibers. The percentage of fibers should range between 10% and 30% of the weight of the bearing portion.
From the following detailed description, taken in conjunction with the accompanying drawings and subjoined claims, other objects and advantages of the present invention will become apparent to those skilled in the art.